NHTSA Complaint #11073410 — 2011 CHEVROLET EQUINOX

I JUST HAD TO REPLACE THE EXHAUST MANIFOLD FOR THE SECOND TIME IN 2 YEARS ON MY 2011 CHEVY EQUINOX DUE TO VERY LARGE CRACKS. THE CAR HAS AROUND 90,000 MILES ON IT AND I REALOZE IT'S 7 YEARS OLD, BUT I TALE PRETTY GOOD CARE OF IT AND GET REGULAR MAINTENCE USUALLY AT AN ACTUAL CHEVY DEALERSHIP. THE FIRST TIME I EXPRESSED MY SUPRISE TO THE MECHANIC WHEN HE YOLD ME THERE WAS A VERY LARGE CRACK IN THE EXHAUST MANIFOLD. HIS RESPONSE WAS THAT CHEVY EQUINOXES ARE WIDELY KNOWN TO GO THROUGH MANIFOLDS QUICKLY AND FREQUENTLY, AGAIN THIS WAS AT AN ACTUAL CHEVY SERVICE STATION AT A CHEVY DEALERSHIP. THE SECOND TIME LESS THAN 2 YEARS LATER WHEN THE CHECK ENGINE LIGHT CAME ON AGAIN I TOOK MY VEHICLE TO TH AAA CERTIFIED CARE CARE CENTER AND AGAIN SAME THING, MANIFOLD LARGE CRACK MUST BE REPLACED AND AAA TECH TOLD ME SAME STORY, CHEVY EQUINOX MANIFOLD ARE WIDELY KNOWN NOT TO LAST. ONLY THIS TIME IN ADDITION TO THE MANIFOLD, THE CRACKED MANIFOLD HAD SOMEHOW CAUSED DAMAGE TO THE CATALYTIC CONVERTER WHICH IS NOW BROKEN AND MUST BE REPLACED. SO MY QUESTION IS, IF THESE ARE WIDELY KNOWN DEFECTS AMONG 2010-2011 CHEVY EQUINOXES, WHY HASNT CHEVY ISSUED RECALLS FOR MANIFOLDS AND CARALYTIC CONVERTERS?